Problem: Khan.scratchpad.disable(); To move up to the maestro level in his piano school, Luis needs to master at least $118$ songs. Luis has already mastered $21$ songs. If Luis can master $8$ songs per month, what is the minimum number of months it will take him to move to the maestro level?
Solution: To solve this, let's set up an expression to show how many songs Luis will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Luis Needs to have at least $118$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 118$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 118$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 8 + 21 \geq 118$ $ x \cdot 8 \geq 118 - 21 $ $ x \cdot 8 \geq 97 $ $x \geq \dfrac{97}{8} \approx 12.13$ Since we only care about whole months that Luis has spent working, we round $12.13$ up to $13$ Luis must work for at least 13 months.